Minor Ash panel related cleanup

ash/wm/window_util.h

Index: ash/wm/window_util.h
diff --git a/ash/wm/window_util.h b/ash/wm/window_util.h
index 3eac811a1a0f044be45b19a36af2a1f55a2b0cab..63c2244e0e03a34971f58a4200d4652781771903 100644
--- a/ash/wm/window_util.h
+++ b/ash/wm/window_util.h
@@ -19,6 +19,7 @@ class Rect;
 }
 
 namespace ui {
+class Event;
 class Layer;
 }
 
@@ -124,6 +125,11 @@ ASH_EXPORT void AdjustBoundsToEnsureWindowVisibility(
     int min_height,
     gfx::Rect* bounds);
 
+// Move |window| to the root window where the |event| occured if it is not
+// already in the same root window.
+ASH_EXPORT void MoveWindowToEventRoot(aura::Window* window,
+                                      const ui::Event& event);
+
 }  // namespace wm
 }  // namespace ash